Source: Ecotelligent homes
Spray foam insulation costs between $.32 and $1.25 per board foot – a one-inch thick layer of foam in a one-square-foot area.
Which type of spray foam insulation you choose plays the most influential role in pricing per board foot.
On top of spray foam type, how much insulation, whether you need to insulate a new or existing home, and whether you hire a pro or not will further spell out your total costs.
To give you a solid idea of whether your insulation project will fall towards the more affordable or expensive side, we detailed each cost factor below.
Hire a local pro for your home insulation project
On this page
- How to calculate spray foam insulation costs
- Open-cell vs. closed-cell spray foam insulation
- Insulation thickness
- Spray foam insulation pros and cons
- Is spray foam insulation worth it?
How to calculate spray foam insulation costs
Professionals calculate spray foam insulation quantities in board feet. Since you can apply foam in varying depths, a board foot is a measurement of volume that takes both the square footage of the to-be insulated area and the foam thickness into account.
length (ft.) * height (ft.) * foam thickness (inches) = board feet
or
square footage * foam thickness (inches) = board feet
Most installers will refer to 1 board foot as a 1-foot by 1-foot area of 1-inch thick foam insulation. Technically, one board foot amounts to one-twelfth of a cubic foot.
1 ft. * 1 ft.* 1 inch = 1 board foot
or
1 square foot * 1 inch = 1 board foot
By this definition, determining how many board feet of insulation you need is relatively straightforward. Let’s say you want to insulate 100 square feet of wall and ceiling in your home with 1-inch thick foam insulation.
100 square feet * 1 inch = 100 board feet
What if you need thicker insulation because you live in a cold climate? Just increase the inches in your equation as desired.
100 square feet * 2 inches = 200 board feet
100 square feet * 3 inches = 300 board feet
100 square feet * 4 inches = 400 board feet
Once you know how much insulation you need, you can estimate costs by multiplying board feet by unit cost per board foot.
Utilizing our estimated average costs – $.25 to $3 per board foot – 100 board feet of spray foam insulation costs between $32 and $125.
Let’s say an insulation contractor charges $1 per board foot of insulation. You can therefore expect to pay $100 for 100 board feet, $200 for 200 board feet, and so on.
The math will not look as clean for spray foam insulation not priced at $1 per board foot, but the cost calculation process remains just as simple!
Open-cell vs. closed-cell spray foam insulation
Unit price primarily comes down to which of the two types of spray foam insulation you choose: open-cell or closed-cell.
Ranging between $1.00 - $1.50 per board foot, closed-cell foam is typically more expensive than open-cell, which costs between $0.44 - $0.65 per board foot.
In turn, your choice plays a key role in the overall cost of spray foam insulation.
What’s the difference between open and closed-cell foam insulation?
Structurally, millions of tiny bubbles, called cells, make up spray polyurethane foam insulation.
Open-cell spray foam insulation does not have fully enclosed cells by design. In practice, this generates a fluffier, porous, low-density foam that expands many multiples of its initial size upon application. Open-cell foam requires less material per board foot than closed-cell to fill a space, hence the lower costs. In difficult-to-reach places, open-cell foam works exceptionally well to minimize air leaks because of how large it expands.
Closed-cell foam, on the other hand, has confined cells. This microscopic structure leads to rigid, high-density foam. At an R-value of 6.25 per inch, closed-cell spray polyurethane foam is one of the most effective home insulation materials money can buy.
It does not expand as much as open-cell, which means you need more material to create an air barrier around gaping spaces. On the plus side, that means you can fit a lot more insulative foam in a limited space to maximize your home’s R-value.
Closed-cell foam eclipses its open-cell counterpart density and higher R-value as it can provide a vapor barrier. This essential component prevents moisture from condensing in cavities that typically lead to costly mold and rot. Given its highly insulative and moisture resistance, closed-cell is also the type of choice for foam roofing.
You will pay more for closed-cell over open-cell per board foot, but the superior insulative properties can recoup the costs in energy savings over the years.
Open-cell SPF | Closed-cell SPF | |
Cost per board foot | $.25-$1.50 | $.90-$3 |
Density | Low | High |
R-value per inch | 3.5 | 6.25 |
Vapor barrier | No | Yes |
Insulation thickness
As with most insulation materials, installers can adjust thickness to achieve the desired R-value.
Every additional inch of spray foam insulation per square foot amounts to one more board foot, which increases costs.
How thick should insulation be?
When determining the spray foam thickness for your insulation project, consult energy efficiency guidelines.
Source: Energy Star
For example, Energy Star recommends uninsulated buildings in Zone 4 receive R38 to R60 worth of attic insulation. Per square foot, that means a minimum of 10.9 inches of open-cell foam (R38 ÷ R3.5 per inch = 10.9 inches) or 6.1 inches of closed-cell insulation (R38 ÷ R6.25 per inch = 6.1 inches.)
The prescribed thickness varies substantially between open and closed-cell. However, do not assume that one type costs more than the other unless you know the unit price for each. If you intend to achieve energy-efficient standards, request estimates from contractors to confirm the most cost-effective course.
Where you install the spray foam insulation
The specific area you need to insulate can dictate whether you need open or closed-cell foam, which we outlined as a central cost factor.
For instance, the basement, rim joist, and other areas where water creates concern typically warrant the use of moisture-resistant closed-cell foam.
A qualified insulation contractor can advise which type of spray foam works best for the area you need to insulate, whether that be the attic, roof deck, HVAC system, or all of the above.
New vs. existing home
Source: Central Kentucky Spray Foam
For wall insulation, installation costs differ considerably between new homes and existing ones.
New construction jobs are ideal for spray foam insulation. Before both the drywall and exterior wall cladding go up, installers can apply insulation with no obstructions.
Finished structures only make insulation installation more complicated. As they already have the outer and inner walls covered up, installers need to create holes to access the wall cavities between studs. After you apply the spray foam, you need to replace the drywall and repaint, which leads to more costs.
Overall, expect to pay more to insulate an existing building.
DIY vs. pro
Source: REenergizeCO
Though you could save a significant sum by opting to do it yourself, spray foam insulation poses notable technical challenges and health risks.
Spray polyurethane foam insulation requires mixing isocyanate and polyol chemicals on-site. Correct application and performance require a balance between spray pressure, mixing ratio, temperature, and humidity. An experienced installer can fine-tune the necessary variables to ensure the spray foam adheres and performs as intended.
However, not every job warrants industrial spray foam equipment. Those $5 hand-held spray foam cans at your local home improvement store will suffice for insulating or air-sealing hairline gaps.
As for safety, the EPA warns of both short and long-term health concerns regarding spray polyurethane foam exposure – an arguably more convincing reason to hire a qualified installer with the necessary equipment.
A contractor always introduces additional costs, but for the sake of quality spray foam installation and your safety, we recommend hiring one regardless.
Spray foam insulation pros and cons
Source: Performance Insulation
Now that you’re familiar with the financials, our overview of its key benefits and drawbacks should paint the complete picture of spray foam insulation.
Spray foam insulation pros
Lower utility bills
What could be better than reduced utility bills every pay period?
With one of the highest R-values among all insulation options, spray polyurethane foam can drastically improve building energy efficiency.
Energy efficiency is crucial for homes in cold climates. According to the Department of Energy, heating makes up around 29 percent of utility bills. Spray foam insulation, particularly closed-cell, maximizes what finite space homes have to insulate with such an impressive R-value.
Tax savings
On top of lower energy costs, you may be able to save during tax time.
If your SPF installation qualifies as an energy-efficient improvement, you can take advantage of the nonbusiness energy property credit.
Easily seals gaps
Spray polyurethane foam not only insulates but also effectively air seals tough-to-access gaps as it quickly expands from its initial liquid state.
In turn, spray polyurethane foam is arguably the best insulation of choice for sealing cracks, crawl spaces, and attics.
Vapor barrier
When using sufficiently thick closed-cell spray foam, your insulation doubles as a vapor barrier.
Vapor barriers prevent moisture in the air from traveling and accumulating inside walls that often link to mold and structural deterioration.
With moisture resistance embedded in your insulation, installers need not apply a separate moisture barrier like polyethylene plastic sheeting, which speeds up and simplifies construction and repairs.
Spray foam insulation cons
High cost
At up to $1.50 per board foot, spray foam insulation costs more than traditional insulation. Fiberglass batt insulation, for example,can go as low as $0.04 per square foot.
If you’re on a strict budget, you may want to steer clear of spray foam insulation.
Health risks
Installers should take extra to prevent exposure to spray foam insulation, which can cause eye, skin, and respiratory irritation.
Due to off-gassing during the curing process, some manufacturers recommend vacating the premises until 24 hours after installation. This can introduce extra costs as well, whether it be due to lost business or temporary housing.
Not DIY-friendly
Although you can pick up a can of spray polyurethane foam at your local Lowe’s, you need at least some training to mix and install it up to professional standards. Then, you need the necessary equipment and chemicals.
Overall, SPF is not the most DIY-friendly insulation material.
Is spray foam insulation worth it?
Source: TruTeam
We didn’t list spray polyurethane foam as one of the best roof insulation options for no reason.
Spray polyurethane foam adheres well to surfaces, seals gaps, and, of course, provides an outstanding R-value per inch.
More importantly, spray foam insulation can reduce energy bills and earn homeowners tax credits.
There are notable caveats, however.
Project costs can soar for homes that warrant extra-thick insulation. Additionally, most homeowners need to hire a contractor specially trained to install SPF, which only adds to the bill.
If you can’t afford a professional contractor or want to insulate your home yourself, spray foam is not for you.
However, if you need to maximize your home’s energy efficiency, spray foam insulation will deliver energy savings handsomely.
Find a local pro to install insulation in your home today
FAQs
Is spray foam worth the money? ›
Spray foam insulation is worth it – in fact, depending on the type of insulation you currently have (or don't have), spray foam insulation could save you up to 50% on your energy bills. Its highly effective heat retention means you simply don't need to use as much energy to heat your home.
How much does it cost to insulate a 24x24 garage? ›A more extensive, double-layer system with an R-30 R-value might cost closer to $1.50 a square foot. So, expect to pay somewhere between about $288 and $864 for materials needed to insulate your 24'x24' metal building.
How many years does spray foam insulation last? ›Both types of spray foam insulation can last anywhere from 80 years to 100 years, with closed cell spray foam having a slight edge in terms of durability. For most families, this represents the lifetime of the house and then some!
Does spray foam insulation add value? ›The answer is yes! In fact, when done correctly and professionally, spray foam insulation can actually increase the value of your home. This type of insulation adds value to any residential property by providing superior energy efficiency, durability, soundproofing capabilities, and more.
What are the negatives of spray foam? ›- It Can Lead to Mold. Spray foam insulation mold problems are quite common. ...
- It Can Have a Foul Odor. Spray foam insulation is mixed on the job site, and improper ratios of chemicals are common. ...
- It Can Lead to Termite Damage. ...
- It's Too Airtight.
2 inches of spray foam is enough in particular situations while using a particular type of foam, but it is not a universally accepted standard for sufficiency. When using closed-cell foam in walls, it is generally considered sufficient when 2 to 3 inches are sprayed.
What is the best cheapest way to insulate a garage? ›What's the Cheapest Way to Insulate a Detached Garage? In most cases, fiberglass batts/rolls are still the simplest and all-around cheapest option for detached garage insulation.
Do insulated garage add value to a home? ›The insulation itself might not make much difference in your ROI, but a higher-quality and higher-priced door can increase the value of your home more than a cheap one. An insulated garage door also gives you personal value immediately after installing it.
Should I spray foam my garage? ›Spray foam (beyond the low-expanding canned product) is excellent for both R-value and air sealing. As a high-end material typically used for energy-efficient construction, spray foam may be overkill for most garage projects. But it might make sense if you're converting the garage to a living space.
Can you sleep in house after spray foam insulation? ›According to the EPA, occupants must stay away from the building while it cures (and as long as the dust remains) for at least 24 to 72 hours, something they, devastatingly, are not always told. If the spray foam continues to off-gas, the building can be inhospitable to occupants for years.
Do you need to remove insulation before spray foam? ›
Any space where spray foam insulation will be installed will need to have the existing insulation completely removed so the new insulation can reach into every nook and cranny. The presence of old insulation can actually prevent spray foam insulation from properly insulating your attic.
Is it safe to be in the house after spray foam insulation? ›During SPF installation, other trade workers and building/home occupants should vacate the premises. Re-entry should be restricted until the product has finished curing, and the building has been adequately ventilated and thoroughly cleaned.
Is spray foam insulation a good choice? ›Spray foam insulation provides excellent thermal performance and the highest R-value (a measure of thermal resistance) per inch for greater potential energy savings compared to other forms of insulation of comparable thickness. The higher the R-value, the greater the insulating properties of a material.
Is spray foam insulation more energy efficient? ›Incredible Energy Saver
Because closed cell spray foam covers nooks and crannies effectively, it provides an excellent air barrier and is extremely energy-efficient. Closed-cell spray foam has been shown to provide energy savings at an average of up to 50% or more.
Closed-Cell Spray Foam Insulation
Closed-cell spray foam has a far better R-value per inch than other, less effective insulations like cellulose, fiberglass, or even open-cell foam. All these have R-values ranging from R-3.2 to R-3.8 per inch. The R-value of closed-cell foam is R-6.5-7 per inch.
Advantages of Blown-In
Since it's blown in, it can fill small gaps and hard-to-reach areas, like spray foam. It's available in fiberglass, the most commonly used insulation material. It's more cost-effective than spray foam and (depending on the material used) can fulfill a wider range of applications.
While spray foam insulation moisture problems are very much real, the moisture problems are not as common as you might think; in fact, spray foam is designed to resist moisture, providing significantly more protection to your home.
What is best attic insulation? ›Fiberglass batt is considered to be the best insulation for attics. Compared to other insulation materials, it is the cheapest and easiest to install. Fiberglass batt is also incredibly energy efficient, as it helps to slow the spread of hot and cold air.
Do I need a vapor barrier with spray foam insulation? ›A vapour barrier is not necessary with closed-cell foam but with open-cell spray foam such as Icynene®, it is sometimes required. Any air that migrates though a building envelope will carry water vapour. As Icynene® spray foam creates a seamless air-seal, it controls air leakage and the moisture in the air.
How much does 1 can of spray foam cover? ›Each can covers approximately 25 Board Feet. Spray-foam insulation is a quick and easy way to seal the gaps in your home and save on energy costs. While many foams require mixing two components out of large canisters, Seal Spray Foam can be applied directly by simply attaching a spray nozzle to the can.
How many square feet does a 55 gallon drum of spray foam do? ›
½# Open Cell Spray Foam 55 gallon kits: 16,000-21,000 board feet coverage We also have Open Cell Spray foam insulation for your project. Open cell is great for sound, and you will get your air barrier at 3.5” thickness.
Why is room above garage cold? ›If the room above your garage feels colder than the rest of your house, it is likely that the cold air is rising through the floor. This is a common problem since most people don't take time to insulate or heat their garages.
What is the best insulation between garage and bedroom? ›Commonly, building companies insulate garage ceilings with fibreglass batts. However, this type of insulation leaves gaps through which the cold air in your garage can pass. Spray foam insulation is much more effective, as it fills the entire ceiling cavity, closing off any paths allowing airflow.
How can I insulate my garage without removing drywall? ›Injection foam insulation is the answer to insulating walls without removing drywall. There are several types of injection foam available out there, including the RetroFoam product we use. These materials don't require the drywall in your home to be taken down.
Should wall between house and garage be insulated? ›Yes, you should because this can be a source for air to move into and out of your home. Any airflow into the garage will come right through that common garage wall into your home. In the same sense, any air you're paying to heat or cool can escape out into your garage.
How much warmer will an insulated garage be? ›By insulating your garage door, you'll help prevent cold air from transferring through the door and be able to keep the garage an average of 10 to 12 degrees warmer.
Does insulation keep heat out of garage? ›Garage insulation is a key cooling factor
Proper insulation will significantly reduce the amount of heat transferred from your garage's exterior to its interior. Insulation will also keep the cool air from your air conditioner from escaping outside.
Spray foam insulation is simply the best for garage insulation. Spray foam seals the air better and performs better than other insulation methods. Spray foam offers a high R-value which means it saves energy costs better than other insulation.
How long does it take to spray foam a garage? ›September 23rd, 2022 | by MPI Foam
Most jobs will take one to two days from start to finish. Both closed-cell and open-cell spray foam insulation will dry and cure fast enough that your family can enjoy the benefits of insulation within hours.
Spray Foam Insulation
About 1.5” of Closed Cell Foam will keep your insulating cost very reasonable, seal your garage from the elements, and insulate any space above or next to your garage from the outside air.
Do you have to drywall over spray foam insulation? ›
Because any type of spray foam is combustible, along with most other building materials, we need to protect the wall from the foam. By installing gypsum board over the foam, we have protection on the inside of the building for a life-saving purpose.
Does spray foam make a house to tight? ›No matter which kind of project you're working on, it is very rare for spray foam to make your new or existing home too tight. Maintaining indoor air quality for both new build and existing homes will require mechanical ventilation, according to the U.S. Department of Energy.
Is spray foam good in an old house? ›For many homeowners, spray foam insulation is an ideal option for making the interior of the house more comfortable and controlling home energy costs. Spray foam insulation is a versatile material with a host of benefits for both new AND older homes.
Does a house with spray foam insulation need venting? ›Yes, attic ventilation is necessary even when using spray foam insulation. Spray foam insulation forms a tight seal around gaps and cracks, preventing air and moisture from entering the attic.
Can you spray foam just the attic? ›(Source: Building Science Corporation.) One technique that can both increase attic insulation and air seal the attic is to apply a layer of spray foam to the attic floor, then to install additional blown-in or batt insulation to meet or exceed insulation R-value requirements.
How do you prepare walls for spray foam insulation? ›Walls need to be framed; electrical and all other wiring should be installed prior to spray foam installation. All wall areas need to be clear so access can be granted for the spray foam installation. All valuables should be masked and or covered with plastic.
What can I use instead of spray foam? ›- Cellulose Insulation.
- Mineral wool insulation.
- Fiberglass batting or roll insulation.
Generally speaking, it's recommended that a building remain empty for eight to 24 hours after insulation installation. We produce polyurethane foam and apply our spray insulation by combining two liquid components into the area to be insulated.
How does a house breathe with spray foam insulation? ›Air will circulate from the living space up to the attic, hit the spray foam barrier, and then move back down. Adding spray foam to the attic flat will seal it off from the rest of your house. The air barrier created with spray foam insulation blocks the air you pay to heat and cool from moving up into the attic.
Why is closed cell spray foam so expensive? ›Since closed cell foam is denser than open cell foam, it will take more material to cover the same amount of space so it will ultimately cost more. Because there is more material being used, there also could be more labor cost to get it installed.
What is better spray foam or fiberglass? ›
Longer lasting, better insulating. First of all, although it may cost a little more upfront, spray foam — both open cell and closed cell — lasts longer and provides better insulation than fiberglass batts.
How long does spray foam take to dry? ›Spraying a mist of water on the substrate or/and between layers of foam can speed up the curing process. Typically, it can take between 5 and 60 minutes for the foam to become tack-free. Full cure may be reached in a time range of about 8 to 24 hours, depending on the product and site conditions.
What are the disadvantages of foam insulation? ›- It Can Lead to Mold. Spray foam insulation mold problems are quite common. ...
- It Can Have a Foul Odor. Spray foam insulation is mixed on the job site, and improper ratios of chemicals are common. ...
- It Can Lead to Termite Damage. ...
- It's Too Airtight.
Putting air leaks to rest is best done with spray foam insulation, which can be applied directly to reduce unwanted air and heat transfer from occurring. The material is capable of expanding to 100 times its liquid volume, thus filling cracks, gaps, holes, and crevices effectively.
Does spray foam insulation last? ›Both types of spray foam insulation can last anywhere from 80 years to 100 years, with closed cell spray foam having a slight edge in terms of durability. For most families, this represents the lifetime of the house and then some!
What is the R-value of 2 inches of spray foam? ›R-Value In 2 Inches Of Spray Foam
The R-value ranges from R-3.5 to R-3.6 per inch. The filling of a 2×4 cavity yields about an R-13.
There are three different levels of density one can choose from when it comes to spray foam insulation—high-density spray foam insulation, medium-density spray foam insulation, and low-density spray foam insulation.
How much difference does spray foam make? ›One of the most significant advantages of spray foam insulation is that it is a better insulator than other types, meaning homeowners can save money on their heating and cooling bills. Closed-cell foam insulation is a powerful insulator with an R-value (thermal resistance) of 6 to 7 per inch of thickness.
Does spray foam make a house stronger? ›Spray foam adds strength to the walls due to the fact that it hardens to the building materials themselves. Other insulation options, like fiberglass batts, sit inside the walls and can move independently of the building.
Will spray foam keep moisture out? ›Spray foam insulation is the only type of insulation that will stop the moisture outside from coming in. Fiberglass insulation and other products don't provide enough of a barrier. You'll have gaps that will allow dampness to come inside. Many of these other insulations can even absorb moisture.
Is spray foam better than other insulation? ›
When compared with other insulation products, spray foam insulation offers the highest R-Value per installed inch. Because spray foam will completely seal and insulate the “building envelope”,, allowing for the ultimate in thermal protection (and R-Value). Spray foam can be closed-cell or open-cell.
When should you not use spray foam insulation? ›Spray foam insulation of any type should not be applied to a substrate or in an air temperature above 120 degrees Fahrenheit. In storage, you also want to keep your spray foam insulation at least 3 inches from any heat source.
How far does 1 can of spray foam go? ›Each can covers approximately 25 Board Feet. Spray-foam insulation is a quick and easy way to seal the gaps in your home and save on energy costs. While many foams require mixing two components out of large canisters, Seal Spray Foam can be applied directly by simply attaching a spray nozzle to the can.
Can you spray foam yourself? ›The answer is yes, but drywall needs to be removed before you can install the foam. Spray foam expands rapidly when it is applied to the inside of walls.
Does spray foam attract bugs? ›Because spray insulation is a synthetic material that hardens, it does not attract insects and rodents in the same way that traditional insulation can.
Will spray foam insulation mold? ›As a product, spray foam insulation does not attract mold. And unlike wood or metal, spray foam does not rot, rust or deteriorate. This means that an area properly sprayed with foam insulation will never become a food source or a hospitable environment for a mold colony.
Is it OK to spray foam attic? ›Closed-cell spray foam is a better choice for keeping subfloor moisture at optimal levels, while open-cell spray foam is a better choice for walls and attics, because it allows homes to “breathe,” Yates said.
What is the best insulation to prevent mold? ›Fiberglass, a non-biodegradable substance is resistant to mold. With its sharp, ground glass, mold spores puncture before they can attach to it. Mold can grow on the fiberglass insulation backing, which is made of paper and is a mold food source. Fiberglass insulation without backing may be the best choice.
What type of spray foam is best? ›Ultimately, closed-cell spray foam is largely the better choice. It's physically stronger and does a better job of insulating a space. It also creates an effective vapor barrier, meaning the homeowner doesn't have to apply one themselves after the foam dries.
What type of spray foam insulation is best? ›Closed cell foam is the best choice for robust insulating where space is an issue, as it can achieve 2x the R-Value of open cell inside a standard wall. Its rigid nature also adds to the structural integrity of the building and E84 fire rated versions are available.